Recently, the use of a proximity sensor has gradually become a main technical trend among the new generation of multifunctional mobile phones. When a mobile phone equipped with a proximity sensor is positioned near a user's ear to actuate a face detection function or is placed in the user's pocket, the proximity sensor is able to immediately turn off the screen of the mobile phone, so as to save the power consumption of the mobile phone and to protect a touchscreen thereof, if any, from unexpected touch or function activation. When a user approaches the mobile phone under a hand-free talking mode to the user's ear, the proximity sensor is able to immediately switch the phone from the hand-free talking mode to a normal mode, so as to make the phone more convenient for use.
The proximity sensor provides not only a smart detection function, but also additional benefit of saving power consumption, and therefore has become many mobile phone manufacturers' best choice. With the benefit of saving power consumption provided by the proximity sensor, consumers using electronic devices equipped with a proximity sensor can enjoy more fun from the extended working hours of the electronic devices. For example, users can play video games, watch video programs, listen to music files, browse websites over Internet, and use many other functions integrated into the electronic devices without being frequently interrupted by short working hours of the electronic devices. When a mobile phone is not in use, the proximity sensor thereof can also, for example, immediately shut off the display screen and/or the keyboard function of the mobile phone. The proximity sensor can also be used to detect whether the cover of a flip-top mobile phone is in a lifted or a closed position.
When being applied to the personal computer, the notebook computer and other peripherals, the proximity sensor can detect surrounding brightness to enable the keyboard backlight or the screen power supply of the computer or the peripherals to be automatically turned on in a dark environment. The proximity sensor enables the provision of a smart keyboard design. That is, when a user moves away from the keyboard, the keyboard backlight or the screen power supply would be automatically shut off to enable to extend battery working hours and computer displayed information to be viewed by unrelated person. Further, when the user does not present in front of the computer, the proximity sensor enables the screen and the computer to automatically shut off and enter into a power-saving standby mode.
However, when the user moves away from a screen or a lamp equipped with a proximity sensor and pushes a chair toward the desk with the computer positioned thereon or put a book or a cup in front of the proximity sensor, or a cat lies down to sleep on the desk in front of the proximity sensor, the proximity sensor would make incorrect determination that the user is still sit before the screen or the lamp, and therefore keeps the screen or the lamp in the on state to cause unnecessary waste of electric energy. Or, it is possible a user watching TV does not move his or her body for quite a long time. In this case, the proximity sensor would not be able to determine whether the user is still sitting before the TV simply by detecting any existence or movement of any object in front of the proximity sensor. That is, it is possible the proximity sensor wrongly determines the user has already moved away from the TV screen and therefore turns off the TV. Such wrong determination surely would bring confusion or inconvenience to the user.